Process for clarification of cane-juice.



To all whom it may concern L I lie it known that I, I)AN1EL'B. RooAN, a

citizen of the United States, residingat New (ll-leans, in the parish. of Orleans-and State v of Louisiana, have invented certain new and PROCESS FOR 'CLARIFICATION 0F CANE-JUICE.

an sir-Ares arana @FFJWE "DANIEL B. noean, or new ORLEANS, noulsra gm.

11 33,910. No Drawing.

useful- Improvements in Processes for Clarification of CaneJuice'; and I do hereby decl are the following to be a full, clear, and exact description of the invention, such' as will enable others skilled in the art to which it appertains to make and use the same. My present invention relates to the clarification of sugar juices, sugar-containing liquids, and particularly to juices expressed from sugar cane and the like, to diluted molasses, and other liquids produced in the manufacture of cane sugar. The object of the invention'is to remove the invert sugar, ordinarily referred to as dextrose, fructose, and also to remove waxy, gummy and similar impurities, and subsequently to remove albuminous and other nitrogenous materials. In carrying out my invention I start with the liquid at about ordinary room temperature,-such a temperature being preferably below 40 (1., although temperatures slightly above this do notcause material injury or loss of sugars.

The liquid is first treated with lime, funtil the same is alkaline in reaction, after and during which operation, the liquid is agitated in any suitable manner. To the liquid is then added a further quantity of lime in order to bring the alkalinity. up to approximately two grams of free lime per gallon,

more or less. Thisliquid, while still at a temperature below about 40 C. is then agitated for a considerable time, by passing a current of air therethrough. The oxygen of the air appears to oxidize some of the con-- stituents, notably the glucose (dextrose) into compounds which unite with lime, under the existing conditions, to produce insoluble The result of this step is tosubstantially completely remove the reduc-'- compounds.

, ing sugars 'or invert sugar, also the precipitation of gums, waxes, and certain'other'melassigenic forming substances. During this operation the degree of alkalinity maybe varied more or less, but it is preferable to maintain,as abovestated, a temperature of approximately 40 C.

When a test shows that the substantially complete removal of the invert sugar has been efi'ected, the cold liquid, still highlyalkaline, is sent to the settling tanks,where the- Specification of Letters Patents P -tented July it, T91 t. Application filed September 30, 1916. Serialhfo. 123,051. 1

precipitate. settles and :the clear liquid, is drawn ofi', or thevliquid may be filtered.

By this operation substantially the entire quantity of. glucose, fructose, and other varietles of reduclng sugars are removed, leave ing a highly clarified and highly pure solution of sugar. All mud, sand, trash, fibers and other similar insoluble materials will be removed by the decantation or filtration, and the removal of certain of the impurities while the liquid is in a cold state, prevents the formation of glucosids, glucosates,sac-

charates and other caramel-like bodies of a melasslgemc character, also removes substances which would tend to darken the sugar and molasses and to retard crystallization and'to increase the viscosity of the sugar syrups at later states of the operation. During this operation the bulk of the Waxes, resins and gums are also-precipitatedin the form of insoluble compounds, and thus removed from the liquid.

The liquid is then treated with a gaseous reagent, such as gases containing carbon dioxid or gas containing sulfur dioxid, until the liquid becomes distinctly acid in reaction. If desired, a portion of the treatment may be efi'ected with carbon dioxid, and the g 1 85 have been efiected in the process, u .to this stage, and none of the losses will ave occurred, which ordinarily do occur when the liquids are treated at temperatures above 1 The liquid in its slightly acid condition is now heated to boiling, for a short time, or

. heated to a higher temperature under pressure, until the albuminous matters and the like are precipitated, and the liquid, after filtration, is readyto be sent to the. evaporators.

In this final step of heating, it sometlmes is inadvisable to heat the juice to as high a point as the boiling point, but a temperature I slightly below' the boiling point, if mamtained for a longer time, isusually suflicient.

earth'ox ids or hydroxide may be employed,

The first principle, however appears to to heat theliquid to not materially below 100 0. at this stage.

In this specification I have referred in numerous places to the use of lime, butl call attention to the fact that other alkaline also in some instances'alkalinevearth carbonates, alkaline earth saccharates or similar actlng substances. If 111116 is employed, it

may be added dry to the liquid, or mayfirst be slaked andmixed with suflicient water to form a paste or aliquid, which liquid may first be cooled if so desired.

at I claim is: 1. In the purification of sugar-containing liquids, the herein described improvement which comprises (61) adding an alkaline earth metal compound capable of neutralizing acids, until an alkaline reaction is produced in the liquid, while said liquid is at a temperature below about 0., (b) adding an excess of such alkaline earth compound, above that required to render the same alkaline in reaction, while still maintaining the.

- temperature below about 40 0., (a) aerating the liquid for an appreciable length of time, while holdingthe temperature below about 40 0., until the reducing sugars are substantially entirely removed from the liquid, and

my and waxy materials in the liquid precipitated, (d).;treating the liquid with a gaseous acid-forming material until the alkalimty of the liquid isneutralized, while still keeping the liquid at a temperature below, 40 0., (e) and thereafter heating to v a-temperature not materially below 100 0.

. earth metal compound capable of neutraliz- 2. In the purification of sugar-containmg liquids, the herein described improvement which comprises (or) adding an alkaline me. tron 1.8 Proin the liquid, while said li uid is at a temperature below about 40 0., adding an excess of such alkaline earth compound,

above that required to render the same alkaline in reaction, while still maintaining the temperature below about 40 0., (c aerating the liquid for an appreciable length of time, while holdin the temperature below about t0 0., ant the reducing sugars are substantially entirely removed from the liquid, and gummy and-waxy materials in the liquid precipitated, (d) treating the liquid with a gaseous acid-forming material until the alkalinity of the liquid is neuthrough the liquid while still at a temperature below 40 0., (0) adding an acid to acid reaction, while still at a temperature below 40 0. addin alkali to partial neutralization while stil below 40 0., and ((1) thereafter heating to about the boiling point.

4. The process of purifying sugar solutions which comprises (a) treating with alkaline earth material in excess, (b) aerating and mixing, (0) gassing to acid reaction, ('11) and partially neutralizing, all of said steps being performed at a temperature below 40 0., and thereafter heating to a temperature of near 100 0.

In testimony whereof, I aiiix my signature.

DANIEL B. ROGAN. 

